Saving your own seeds is cost effective and rewarding, however some seeds are harder to save than others. This page looks at the different ways vegetable seeds are pollinated and the relative difficulties of saving them.
This Vegetable Seed Saving Suitability guide page is mainly for gardeners living in urban areas. It does not give minimum distance requirements between compatible cross pollinating plants, nor does it list minimum numbers of plants needed to maintain genetic variety. That is because urban gardeners do not have the garden space to meet these requirements. What this guide does do is try and factor in this lack of minimum distance requirements and limited number of plants options when determining the different levels of difficulty in saving seeds.
SELF POLLINATED (Easy)
These plants are the easiest to collect seeds from as the seeds will always grow exactly like the parent plant. Plants in this group include Bean, Endive, Lettuce, Okra, Pea and Tomato.
PROPAGATED VEGETATIVELY (Easy)
These plants only propagate vegetatively, meaning that to grow new plants you plant cutting, root, or bulb (depending on the type of plant). Plants in this group include Garlic, Lemongrass, Potato, Tarragon, Tree Onion and Water Chestnut.
PROPAGATED VEGETATIVELY AND CROSS POLLINATED BY INSECTS (Easy, when saved vegetatively)
Propagated by a cutting, root, or bulb (depending on the plant) and will also produce cross pollinated seeds. The simplest way to propagate these plants is vegetatively. Plants in this group include Asparagus, Chives, Garlic Chives, Jerusalem, Artichoke, Leek, Marjoram, Mint, Rhubarb, and Spring Onion.
POLLINATED BY WIND (Moderate to hard)
Cross pollinated by wind only, so only cross pollinates with plants of the same variety that are in the immediate area. Plants in this group include Corn and Spinach.
BOTH SELF-POLLINATED AND CROSS POLLINATED BY INSECT (Moderate to hard)
Will self-pollinate but can also be cross pollinated by insects. Plants in this group include Broad Bean, Capsicum, Chilli and Eggplant.
CROSS POLLINATED BY INSECTS (Moderate to hard)
These are the hardest types of seeds to collect as they can easily crosspollinate with other types of plants of the same species. Plants in this group include Basil, Broccoli, Cabbage, Carrot, Cauliflower, Celery, Cucumber, Fennel, Kale, Kohlrabi, Mizuna, Mustard, Onion, Parsley, Parsnip, Pumpkin, Radish, Rocket, Rockmelon, Silverbeet, Sunflower, Turnip, Watermelon and Zucchini.
* Note that these categories are based on information drawn from four seed saving pollination charts. There is some variation in the levels of difficulty between these charts, hence these categories may not be entirely accurate.
While these seed saving categories are a good guide to work from my experiences of saving seeds does not always match them. Below is a list of some of the vegetables that I have saved seeds from, along with comments on how they fared and where my experiences differ from the above categories.
ASPARAGUS (Propagated vegetatively and cross pollinated by Insects)
I have only ever propagated asparagus vegetatively. This is because: –
- The crowns used to propagate asparagus vegetatively are clones of the parent plant, which means they will be exact copies. Whereas asparagus plants grown from seed may turn out to be quite different from the parent plant.
- Asparagus grown from seed will take three years to harvest, whereas planting crowns only takes two years.
- Asparagus is vulnerable to attacks from slugs and snails when small and asparagus grown from seed is extremely small in its first year.
Unless you are wanting to produce a large number of asparagus plants cheaply it is better to propagate asparagus vegetatively than from seed.
CORN (Cross pollinated by wind)
While corn is listed as difficult to save seeds from it is in fact almost impossible to save its seeds in an urban setting. This is because corn needs at least 10 plants to produce viable seeds and 50 to 100 plants to maintain the variety. Saving such a large number of cobs is not practicable in an urban setting.
My experience of planting saved corn seeds was that they had a higher risk of producing infertile cobs. I concluded that it was not worth using saved corn seeds as the risk of inbreeding was too high. These days I only plant bought corn seeds.
CHILLIES AND CAPSICUMS (Both self -pollinated and cross pollinated by insect)
Capsicums and chilli plants are considered moderately difficult to save seeds from. But while they will cross pollinate with each other, because they also self-pollinate the risk of cross pollination is lower than with plants that only reproduce by cross pollination. Though I have found capsicum and chilli plants easy to save seeds from, they will eventually cross. When that happens you will have to discard your saved seeds and buy new seed stock.
CARROT (Cross pollinated by insects)
Carrots are considered moderately difficult to save seeds from as they need to cross pollinate with other types of plants of the Daucus carota family to produce fertile seeds. However, I have found it easy to save carrot seeds as they generally stay true to type. Carrots will cross pollinate with other varieties of carrots and with wild variants such as Bishop’s Lace, and Queen Anne’s lace. But when I save carrot seeds where cross pollination has occurred the carrots that are produced usually still look like carrots and are still good to eat. Occasionally I get the odd small purplish carrot, which would probably be a cross with one of the wild variants, but such throwbacks are rare.
MIZUNA (Cross pollinated by insects)
Although the member of the mustard family, which is both large (plenty of varieties to cross pollinate with) and readily cross pollinates, I have found it largely stays true to type. So far, all the Mizuna seeds I have saved have remained true to type.
ROCKET (Cross pollinated by insects)
Rocket (Arugula) is considered difficult to save seeds from as it readily crosses with other members of the mustard family (E.G. cauliflower, broccoli, and cabbage). It is easy to save the seeds from, but I have found that what is saved often produces a coarser poorer quality leaf plant. But because its life cycle is so short before going to seed it is easy to test its quality without expending much time and effort. You will occasionally get a good batch of seed.
My Personal Experience Pollination Comparison
Saving seeds from vegetables that are cross pollinated by insects is harder due to the risk of cross pollination producing seeds that are not true to type. But there are some things you can do to reduce that risk. They are :-
- PRACTICE ON TRACK SEED SAVING
Which is keeping saved seeds when they produce the same plants as the parent plants but discarding them as soon as they show clear signs of genetic drift.
- SAVE SEEDS NO MORE THAN THREE TIMES
Every generation of seeds that you save yourself increases the risk of cross pollination genetic contamination. Seeds rarely get beyond three generations before that contamination significantly changes the characteristics of seeds’ plants.
- USE A BATCH OF GOOD SAVED SEEDS UNTIL THE END OF THEIR USE BY DATE
Once you have saved cross pollinated seeds that are true to type use those seeds each year until they are nearing their use by storage date. There is no need to save seeds from that variety every year. This is a good practice regardless of the cross pollination risk as, when saving seeds, you usually get enough seeds to last several years.
- LIMIT THE NUMBER OF VARIETIES THAT YOU GROW
The fewer varieties of a vegetable that you grow the less chance of cross pollination between the varieties.
PLANT VEGETABLES OF THE SAME VARIETY CLOSE TO EACH OTHER
That way when a bee (the most common form of insect cross pollination) transports pollen from one plant to another it is more likely to be cross pollinating plants of the same variety. Grouping varieties together works particularly well with vegetables that both self and cross pollinate, such as capsicum, chilli, and eggplant.
There are more sophisticated techniques for saving seeds that are cross pollinated by insects, such as covering plants or induvial flowers with insect proof netting and hand pollinating, but I have little experience in these practices.